meconium aspiration syndrome
Also written as: MAS
A respiratory condition in newborns caused by inhalation of meconium-stained amniotic fluid, resulting in airway obstruction and chemical pneumonitis.
Full Definition
Meconium aspiration syndrome (MAS) occurs when a newborn inhales meconium-stained amniotic fluid during delivery or in utero, leading to airway obstruction, surfactant inactivation, and chemical pneumonitis. The condition typically affects term or post-term infants who have passed meconium in utero due to fetal stress. Radiographic findings include bilateral patchy infiltrates with areas of hyperinflation and atelectasis, creating a characteristic 'rope-like' or 'coarse' pattern. Complications include pneumothorax, pneumomediastinum, and persistent pulmonary hypertension of the newborn (PPHN). Pediatric radiologists must recognize the imaging evolution of MAS, from initial aspiration patterns to potential complications requiring urgent intervention. Serial chest radiographs are often necessary to monitor progression and identify complications such as air leak syndromes.
Usage
Usage note: Often abbreviated as MAS in clinical documentation and radiology reports.
In Context
- "The bilateral coarse infiltrates and hyperinflation were consistent with meconium aspiration syndrome." — Neonatal chest radiograph report
- "Meconium aspiration syndrome was complicated by pneumothorax requiring chest tube placement." — NICU progress note